Printing apparatus, method of controlling the same, and storage medium

ABSTRACT

A printing apparatus causes a printer engine to print first tone correction patches of a first color on a first sheet and to print second tone correction patches of a second color being different from the first color on a second sheet, generate correction information based on a color measurement result of the first tone correction patches and the second tone correction patches printed on the first sheet and the second sheet, respectively, as measured by a sensor, and correct image data using the correction information. In the generation of the correction information, in a case where there are more than a predetermined number of sheets of a size being different from a predetermined size between the first sheet and the second sheet, the correction information using the color measurement result of the first tone correction patches and the second tone correction patches is not generated.

This application is a continuation of application Ser. No. 17/348,924,filed Jun. 16, 2021.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a printing apparatus, a method ofcontrolling the same, and a storage medium.

Description of the Related Art

A known image forming apparatus renders page description language (PDL)data sent via a network from an information processing terminal or animage control apparatus into a bitmap and forms an image on a sheetaccording to the rendered image data.

Also, in a known printing system, an inline sensor is connected to thedownstream side of an image forming apparatus that forms an image on asheet, and the inline sensor reads the image formed on the sheet by theimage forming apparatus. In such a printing system, the inline sensorreads a patch printed in the margin area of the print matter by theimage forming apparatus for adjusting the image forming position and theimage quality. This allows feedback relating to an adjustment result ofthe image forming apparatus to be given to the image forming apparatusin real time.

However, because a region of the margin area of the print matter islimited, patches needed for adjusting may be unable to be accuratelyprinted by the image forming apparatus. In Japanese Patent Laid-Open No.2017-32922, a technology is described that, in a case where patches foradjusting an image forming position and patches for adjusting an imagequality are printed on one sheet at the same time but overlap oneanother, reduces the number of gradations in the patches for adjustingthe image quality and performs printing such that the patches do notoverlap.

Consider a case where a sheet of a size that can accommodate a regionfor forming the necessary patches and a sheet of a size that cannotaccommodate the region are both present. In the method described inJapanese Patent Laid-Open No. 2017-32922, patches with a reduced numberof gradations are printed on the sheet with a size that cannotaccommodate the region.

However, with the known technology described above, because the patchesprinted have a reduced number of gradations, the adjustment accuracy ofthe image quality is reduced.

SUMMARY OF THE INVENTION

An aspect of the present invention is to eliminate the above-mentionedproblem with conventional technology.

A feature of the present invention is to provide a technique forperforming accurate image quality adjustment in which tone correctionpatches are printed on a sheet in real time, even in a case of acombination including a sheet with a size able to accommodate thepatches on a single sheet and a sheet that is unable to accommodate thepatches on a single sheet.

According to a first aspect of the present invention, there is aprinting apparatus comprising: a printer engine that prints an image ona sheet; a sensor that performs color measuring of tone correctionpatches printed on a sheet, the patches including at least a set offirst color tone correction patches and a set of second color tonecorrection patches; a controller including at least one processor and atleast one memory being configured to cause the printing apparatus to:correct image data for printing on the basis of a color measurementresult obtained by the sensor; control to cause, in a case where thetone correction patches are to be printed on sheets respectively havinga predetermined size, the printer engine to print the set of the firstcolor tone correction patches on a first sheet with the predeterminedsize and to print the set of the second color tone correction patches ona second sheet with the predetermined size; and execute control suchthat, in a case where the first sheet and the second sheet with thepredetermined size are printed one after another, a color measurementresult of the tone correction patches printed on the first sheet and thesecond sheet are used in correcting the image data for printing.

According to a second aspect of the present invention, there is provideda method of controlling a printing apparatus including a printer enginethat prints an image on a sheet and a sensor that performs colormeasuring of tone correction patches printed on a sheet, the patchesincluding at least a set of first color tone correction patches and aset of second color tone correction patches, the method comprising:correcting image data for printing on the basis of a color measurementresult obtained by the sensor; controlling to cause, in a case where thetone correction patches are to be printed on sheets respectively havinga predetermined size, the printer engine to print the set of the firstcolor tone correction patches on a first sheet with the predeterminedsize and to print the set of the second color tone correction patches ona second sheet with the predetermined size; and executing control suchthat, in a case where the first sheet and the second sheet with thepredetermined size are printed one after another, a color measurementresult of the tone correction patches printed on the first sheet and thesecond sheet are used in correcting the image data for printing.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention.

FIG. 1 is a schematic diagram illustrating the overall configuration ofa printing system according to an embodiment of the present invention.

FIG. 2 is a block diagram for describing the hardware configuration of aprinting apparatus according to the embodiment.

FIG. 3 is a functional block diagram for describing the softwareconfiguration of the printing apparatus according to the embodiment.

FIGS. 4A and 4B are diagrams for describing the basic operation sequencewhen margin-use type printing processing is executed using the printingapparatus according to the embodiment.

FIG. 5 is a diagram for describing the process of clearing the referenceinformation and the correction information in the printing apparatusaccording to the embodiment.

FIG. 6A is a flowchart for describing the processing to clear thereference information and the correction information for each sheet typeexecuted by the printing apparatus according to the embodiment.

FIG. 6B is a flowchart for describing the processing to register thereference information and the correction information for each sheet typeexecuted by the printing apparatus according to the embodiment.

FIGS. 7A and 7B depict views illustrating examples of screens forregistering sheet types with sheet feeders of the printing apparatusaccording to the embodiment.

FIGS. 8AA and 8AB are diagrams for describing information of amanagement table of the printing apparatus according to the embodiment.

FIGS. 8BA, 8BB, and 8BC are diagrams for describing information of amanagement table of the printing apparatus according to the embodiment.

FIG. 9 is a diagram illustrating an example of a table indicatingwhether the sheet is a large size sheet or a small size sheet.

FIGS. 10A and 10B are diagrams illustrating output examples of patchestargeted for real time multi-tone correction according to sheet sizethat are output by the printing apparatus according to the embodiment.

FIG. 11 is a flowchart for describing the processing to determinewhether or not to perform real time multi-tone correction using theprinting apparatus according to the embodiment.

FIGS. 12A to 12C are diagrams illustrating examples of sheets on whichpatches for real time multi-tone correction have been printed.

DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present invention will be described hereinafter indetail, with reference to the accompanying drawings. It is to beunderstood that the following embodiments are not intended to limit theclaims of the present invention, and that not all of the combinations ofthe aspects that are described according to the following embodimentsare necessarily required with respect to the means to solve the problemsaccording to the present invention.

FIG. 1 is a schematic diagram illustrating the overall configuration ofa printing system according to an embodiment of the present invention.

In the printing system, a printing apparatus 101 and an informationprocessing terminal 102 are connected to one another via a local areanetwork (LAN) cable 100. The printing apparatus 101 is capable ofexecuting a print job received from the information processing terminal102.

FIG. 2 is a block diagram for describing the hardware configuration ofthe printing apparatus 101 according to the embodiment.

The printing apparatus 101 includes a print function for printing animage on a sheet (paper). This embodiment is described using theprinting apparatus 101 as an example. However, a multi-functionperipheral (MFP) or similar printing apparatus that includes a printingapparatus, a scanner, and a fax function may be used. Also, the printingapparatus may be divided into an image control apparatus (printerdriver) and an image output apparatus (printer), with the image outputapparatus and the image control apparatus being connected via a videocable and a LAN cable. Also, the printing apparatus may be divided intoan image control apparatus and an image output apparatus, with the imageoutput apparatus and the image control apparatus being connected viaonly a LAN cable.

A control unit 200 including a central processing unit (CPU) 201controls the entire operations of the printing apparatus 101. The CPU201 deploys a program stored in a read-only memory (ROM) 202 or astorage 204 into a random-access memory (RAM) 203, executes the deployedprogram, and executes various controls including print control and readcontrol. The ROM 202 stores control programs, boot programs, and thelike that are executable by the CPU 201. The RAM 203 is a main storagememory of the CPU 201 and is used as a working area or temporary storageregion to deploy various control programs. The storage 204 stores printdata, image data, various programs, and various settings information. Inthis embodiment, the storage 204 is expected to be an auxiliary storageapparatus such as a hard disk drive (HDD) or the like. However, anon-volatile memory such as a solid state drive (SSD) or the like may beused. Note that in the printing apparatus 101 according to theembodiment, one CPU 201 uses one memory (the RAM 203) to execute theprocessing described in the flowchart described below. However, otherconfigurations may be used. For example, a plurality of CPUs, RAMs,ROMs, and storages may cooperate to execute the processing described inthe flowchart described below. Also, parts of the processing may beexecuted using a hardware circuit, such as an Application SpecificIntegrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), andthe like.

A console unit interface (I/F) 205 connects a console unit 206 to thecontrol unit 200. The console unit 206 is provided with a display unitwith touch panel functionality, various hard keys, or the like andfunctions as a display unit that displays information and a receptionunit that receives user instructions. An image processing unit 207 isprovided with a raster image processor (RIP) function that renders datain a print job received via a communication unit I/F 208 into image datato be printed. Also, the image processing unit 207 is capable ofexecuting resolution conversion or correction processing of the imagedata obtained by rendering the data of the print job. Note that in thisembodiment, the image processing unit 207 is expected to be implementedwith a hardware circuit (ASIC, FPGA, or the like). However, no suchlimitation is intended. For example, the printing apparatus 101 mayfurther include a processor for image processing, and image processingand processing for rendering into image data may be executed by thisprocessor executing an image processing program. In this case, thisprocessor and the CPU 201 cooperate to implement processing as shown inthe flowcharts described below. Furthermore, a configuration is possiblein which the CPU 201 executes a program for executing image processingto execute image processing and rendering processing. Also, theseconfigurations may be combined to execute image processing.

A printing unit (printer engine) 209 prints an image on a sheet feedfrom a feeding cassette (not illustrated) on the basis of image datagenerated by the image processing unit 207. Note that the printingmethod of the printing unit 209 may be an electro-photographic method oran inkjet method. Another printing method such as a thermal transfermethod may be used. A color measuring unit 210 uses a CIS color sensorto measure, at a position downstream of the sheet conveyance path of theprinting unit 209, the colors of the tone patches of each color of atone correction mark formed on the printed sheet and obtains colormeasurement data. The control unit 200 connects to the LAN 100 via thecommunication unit I/F 208. The communication unit I/F 208 receives aprint request (print job) from the information processing terminal 102on the LAN 100. Note that in this embodiment, the printing system is asillustrated in FIG. 1 . However, the present invention is not limitedthereto, and it is only required that one or more information processingterminals and a printing apparatus are communicatively connected via anetwork. Also, the network may be a wireless or a wired network.

FIG. 3 is a functional block diagram for describing the softwareconfiguration of the printing apparatus 101 according to the embodiment.Note that the functions of the units illustrated in FIG. 3 areimplemented by the CPU 201 executing a program deployed on the RAM 203.

A print job generation module 301 generates a print job to be executedby the printing apparatus 101 when a job is input and registers theprint job in a job control module 303. A data receiving control module302 receives PDL data transmitted from the information processingterminal 102 via the communication unit I/F 208. The job control module303 instructs a page control module 304 to start processing all of thepages included in the registered print job in order from page 1 andmakes the page control module 304 start page processing. Then, when thejob control module 303 is notified by the page control module 304 thatprocessing of the next page can be started, the job control module 303instructs the page control module 304 to start processing the next page,with this process repeating. Also, when the job control module 303receives a notification from the page control module 304 that processingof all the pages is complete, the print job generation module 301 isnotified of job completion. The page control module 304 receives a pageprocessing start notification from the job control module 303 andcontrols the processing of the pages. A PDL analyzing module 305analyzes the received PDL data and converts it into intermediate data. ARIP control module 306 rasterizes the intermediate data and converts itinto image data in a bitmap format. An image generation module 307reflects the correction information for the sheet to be used in printingto the generated bitmap image data and generates corrected image data(print image data) for printing. Then, the print image data istransferred to a patch combining module 309 of an engine control module308. The image generation module 307 controls the image processing unit207.

The engine control module 308 includes the patch combining module 309, acorrection information storing module 310, a reference informationstoring module 311, a color measuring sensor control module 312, a sheetfeeder managing module 313, a feed control module 314, and a printcontrol module 315. The color measuring sensor control module 312controls the color measuring unit 210. Also, the engine control module308 controls the patch combining module 309, the correction informationstoring module 310, the reference information storing module 311, thesheet feeder managing module 313, and the feed control module 314; andthe print control module 315 controls the printing unit 209.

The patch combining module 309 combines tone correction mark information(tone patches) with print image data such that tone correction marks(patches) are formed in addition to an image formed on the basis of thecorrected print image data received from the image generation module307. Also, the patch combining module 309 instructs the print controlmodule 315 to print the combined image data. The correction informationstoring module 310 holds reference information to be held by thereference information storing module 311 and correction informationobtained by comparison of the color measurement data obtained by thecolor measuring sensor control module 312 for each type of sheet set inthe sheet feeders. Herein, reference information is a color measurementresult, sheet feeder, sheet size, sheet type, and similar informationnotified of by the color measuring sensor control module 312 describedbelow. Correction information is information calculated from storedreference information and a color measurement result notified by thecolor measuring sensor control module 312.

The reference information storing module 311 holds reference informationgenerated based on color measurement data obtained by the colormeasuring sensor control module 312 for each type of sheet set in thesheet feeders. The color measuring sensor control module 312 controlsthe color measuring unit 210 to measure the tone correction marks formedon the sheet and obtains a color measurement result.

The sheet feeder managing module 313 manages information of the sizesand types of the sheets set in all of the sheet feeders of the printingapparatus 101. Also, the sheet feeder managing module 313 clears thereference information for sheet types to be removed for replacement heldin the reference information storing module 311 in response to a sheetregistration request from a UI control module 316. Furthermore, in acase where correction information for sheet types to be removed forreplacement is held by the correction information storing module 310,the sheet feeder managing module 313 clears this correction information.The feed control module 314 controls the sheet feeders according to aprint job and conveys and supplies the sheets housed in the sheetfeeders. The print control module 315 prints on a sheet supplied by thefeed control module 314 on the basis of image data that has been tonepatch combined and discharges the printed sheet. In this embodiment, animage may be formed on a sheet on the basis of image data with tonecorrection mark information (tone patches) added thereto as appropriate.

When the user operates the console unit 206 and sets sheet informationto the sheet feeder, the UI control module 316 requests sheetregistration for the sheet feeder managing module 313. Also, UI controlmodule 316 displays information of the registered sheets on the consoleunit 206. The UI control module 316 controls the console unit 206.

Next, a basic sequence of printing processing for printing colormeasuring patches for tone correction on a printed sheet, measuring inreal time with a color measuring sensor, and continuously givingfeedback for the correction information for the next page is provided.Hereafter, this control is referred to as real time multi-tonecorrection.

There are two types of real time multi-tone correction: a margin-usetype in which patches are printed using a margin area of the outputsheet and a chart-insertion type in which, in a case where the marginarea of the output sheet cannot be used, a dedicated sheet to insertedand patches are printed. With the margin-use type, patches are printedon each page in the margin area of the print data inserted by the userand feedback correction is performed. With the chart-insertion type, adedicated sheet on which patches have been printed at insertionintervals set in advance in the printing apparatus 101 is inserted andfeedback correction is performed. The user instructs the printingapparatus 101 whether to perform real time multi-tone correction usingthe margin-use type or the chart-insertion type when entering a printjob.

FIGS. 4A and 4B are diagrams for describing the basic operation sequencewhen margin-use type printing processing is executed using the printingapparatus 101 according to the embodiment. The sequence is implementedby the CPU 201 of the printing apparatus 101 deploying a program storedin the ROM 202 on the RAM 203 and executing the program.

The print job generation module 301 generates a print job according tothe job received from the communication unit I/F 208. Then, in stepS401, the print job generation module 301 registers the generated printjob in the job control module 303. In response to this, in step S402,the job control module 303 determines the execution order of theregistered print jobs and starts order processing. When the processingof the job control module 303 starts, in step S403, the job controlmodule 303 notifies the page control module 304 of the start of theprocessing of the Nth page. When the page control module 304 receivesthe start notification of the processing of the Nth page from the jobcontrol module 303, in step S404, the page control module 304 queriesthe sheet feeder managing module 313 for which sheet feeder to feed fromfor the sheet size and sheet type designated for the page. In responseto this, in step S405, the sheet feeder managing module 313 determineswhich sheet feeder to feed from on the basis of the designated sheetsize and sheet type and returns the result to the page control module304.

In step S406, the page control module 304 instructs the feed controlmodule 314 to feed from the sheet feeder determined by the sheet feedermanaging module 313. In response to this, in step S407, the feed controlmodule 314 performs feeding from the instructed sheet feeder inaccordance with the feeding instruction from the page control module304. Then, in step S408, the page control module 304 is notified of thisfeeding result. When a normal feeding result is received from the feedcontrol module 314, in step S409, the page control module 304 notifiesthe job control module 303 that processing can be started of the nextpage. Also, when a normal feeding result is received from the feedcontrol module 314, in step S410, the page control module 304 instructsthe image generation module 307 to generate image data and to transferthe image data. At this time, the page control module 304 notifies theimage generation module 307 of the sheet feeder used, sheet size, andsheet type.

When the image generation module 307 receives an instruction to generateimage data and to transfer the image data, in step S411, the imagegeneration module 307 requests correction information for the correctioninformation storing module 310 on the basis of the notified sheetinformation. In response to this, in step S412, the correctioninformation storing module 310 searches for whether the correctioninformation corresponding to the information passed on is stored in theRAM 203. Then, when the correction information storing module 310detects the corresponding correction information, in step S413, thecorrection information storing module 310 notifies the image generationmodule 307 of the correction information. In response to this, in stepS414, the image generation module 307 uses the correction informationfrom the correction information storing module 310 to generate imagedata to be printed.

On the other hand, in a case where the correction information storingmodule 310 cannot detect correction information corresponding to theinformation passed on from the image generation module 307, in stepS415, the correction information storing module 310 informs the imagegeneration module 307 that there is no correction information. In a casewhere there is no correction information, in step S416, the imagegeneration module 307 generates image data without correctioninformation. Then, in step S417, the image generation module 307transfers to the patch combining module 309 the generated image data andthe sheet feeder, sheet size, and sheet type information notified of bythe page control module 304.

In step S418, the patch combining module 309 combines tone adjustmentmark information (tone patches) with a margin area of the image datatransferred by the image generation module 307. Next, in step S419, thepatch combining module 309 transmits, to the print control module 315,the generated combined image data and the sheet feeder, sheet size, andsheet type information notified of by the image generation module 307and issues a print instruction. Then, in step S420, the print controlmodule 315 prints the received image data (the image data combined withthe tone adjustment mark information) on a sheet supplied by the feedcontrol module 314. When printing is complete, in step S421, the printcontrol module 315 notifies the page control module 304 and the colormeasuring sensor control module 312 of printing completion (dischargecompletion). The notification of printing completion (dischargecompletion) includes the sheet feeder, sheet size, and sheet typeinformation. When the printing completion (discharge completion)notification is received from the print control module 315, in stepS422, the page control module 304 notifies the job control module 303 ofthe completion of the processing of the Nth page.

On the other hand, when the printing completion (discharge completion)notification is received from the print control module 315, in stepS423, the color measuring sensor control module 312 performs colormeasuring of the tone adjustment marks (tone patches) printed in stepS420. Then, in step S424, the reference information storing module 311is notified of information of the color measurement result and the sheetfeeder, sheet size, and sheet type information notified of by the printcontrol module 315 associated with one another.

In step S425, the reference information storing module 311 searches forwhether reference information corresponding to the information notifiedof by the color measuring sensor control module 312 is stored in the RAM203. Then, in a case where the reference information corresponding tothe notified information is stored, in step S426, correction informationis calculated from the stored reference information and the colormeasurement result notified by the color measuring sensor control module312. Next, in step S427, the reference information storing module 311notifies the correction information storing module 310 of the calculatedcorrection information. Then, in step S428, the correction informationstoring module 310 stores the contents (correction information) notifiedby the reference information storing module 311 as correctioninformation. On the other hand, in step S425, in a case the referenceinformation is not stored, in step S429, the reference informationstoring module 311 stores the information (color measurement result,sheet feeder, sheet size, sheet type, and the like) notified by thecolor measuring sensor control module 312 in the RAM 203 as referenceinformation (initial information).

Note that in this embodiment, the processing from step S403 to step S425is indicated by “LOOP” meaning that this processing is repeatedlyexecuted on all of the pages of the print job registered in the jobcontrol module 303. The start processing on each page indicated in stepS403 can be issued when the notification of step S409 indicating thatprocessing of the next page can start is received.

When the job control module 303 receives processing completion of theNth page, in step S430, the job control module 303 determines whether ornot the Nth page is the last page of the print job. Then, when the jobcontrol module 303 determines that the completion of the last page hasbeen received, in step S431, the print job generation module 301 isnotified of job completion.

FIG. 5 is a diagram for describing the process of clearing the referenceinformation and the correction information in the printing apparatus 101according to this embodiment. The processing indicated by this processis implemented by the CPU 201 of the printing apparatus 101 deploying aprogram stored in the ROM 202 on the RAM 203 and executing the program.

When the printing apparatus 101 prints an image on a sheet, because thecharacteristics for printing an image differs depending on the type ofsheet, the printing apparatus 101 needs to hold reference informationfor each type of sheet for tone correction to be correctly performed.The printing apparatus 101 is capable of using many types of sheets.However, the sheets actually used need to be set in the sheet feeder.Thus, the reference information storing module 311 holds only thereference information of the type of sheet set in the sheet feeder.Accordingly, when the user sets a new type of sheet in the sheet feederof the printing apparatus 101, the reference information and thecorrection information corresponding to the type of sheet being removedfor replacement must be cleared.

In step S501, the user operates a UI screen displayed on the consoleunit 206 of the printing apparatus 101 and selects the feeder settingsscreen. In step S502, when the UI control module 316 of the printingapparatus 101 receives a user operation, the UI control module 316obtains the information of the size and type of all of the sheets set inthe sheet feeders of the printing apparatus 101 from the sheet feedermanaging module 313. Then, in step S503, the UI control module 316displays the information obtained in step S502 on the UI screen of theconsole unit 206.

FIG. 7A depicts a view illustrating an example of a UI screen 700displayed at this time.

In step S504, the user selects the sheet feeder with the sheet they wishto change via the UI screen 700. In FIG. 7A, selection buttons 701 to704 correspond to the sheet feeders of the printing apparatus 101. Instep S505, when a user operation is received, the UI control module 316of the printing apparatus 101 displays, on the UI screen, a list of thetype of sheets able to be set in the sheet feeder corresponding to theselected selection button. In FIG. 7A, the selection button 701 isselected.

FIG. 7B depicts a view illustrating a display example of a list 710 ofthe type of sheets able to be set in the sheet feeder corresponding tothe selection button.

In step S506, the user selects the type of sheet they wish to changefrom the list 710 of sheet types. In step S507, when a user operation isreceived, the UI control module 316 of the printing apparatus 101requests the sheet feeder managing module 313 to register the sheetfeeder selected by the user and the sheet type. In the example of FIG.7B, the request is to change the sheet of the sheet feeder correspondingto the selection button 701 to “plain paper 3” indicated by referencenumber 707. Accordingly, in step S508, the sheet feeder managing module313 updates the information stored in the reference information storingmodule 311 and the correction information storing module 310. The updateprocessing will be described in detail below with reference FIGS. 6A and6B. Note that the screens of FIGS. 7A and 7B will be described infurther detail below with reference to the sequence of FIG. 5 .

When the sheet feeder managing module 313 determines that it isnecessary to clear the reference information and the correctioninformation on the basis of the flowchart of FIG. 6A, processing toclear the reference information and the correction information, stepS509 and step S510 respectively, is executed. In step S509, the sheetfeeder managing module 313 clears the reference information for the typeof sheet to be removed for replacement stored in the referenceinformation storing module 311. Also, in step S510, the sheet feedermanaging module 313 determines whether correction information for thetype of sheet to be removed for replacement is present in the correctioninformation storing module 310 and, in a case where it is present,clears the correction information. Then, when the processing series ofstep S508 is complete, in step S511, the sheet feeder managing module313 executes processing to register the type of sheet designated by theuser (updates the information of the sheet set in the selected sheetfeeder). In step S512, the sheet feeder managing module 313 notifies theUI control module 316 of registration completion. In step S513, the UIcontrol module 316 updates the UI screen with the information of thetype of sheet for which registration has been completed.

FIG. 6A is a flowchart for describing the processing to clear thereference information and the correction information for each sheet typeexecuted by the printing apparatus 101 according to the embodiment.Also, FIG. 6B is a flowchart for describing the processing to registerthe reference information and the correction information for each sheettype executed by the printing apparatus 101 according to the embodiment.The processing of both flowcharts is implemented by the CPU 201 of theprinting apparatus 101 deploying a program stored in the ROM 202 on theRAM 203 and executing the program.

First, FIG. 6A is a flowchart for describing processing to clear thereference information and the correction information in which, whenthere is a request to register the sheet feeder and the sheet typeselected by the user in step S507 of FIG. 5 as described above, in stepS509 and step S510, the CPU 201 functions as the sheet feeder managingmodule 313.

In step S601, the CPU 201 receives a request to register the sheetfeeder and the sheet type selected by the user. Next, the processproceeds to step S602, and the CPU 201 determines whether or not theregistration request leads to a change in sheet type. In a case where nochange is needed (re-register of the same sheet type), the process ends.On the other hand, when the sheet type needs to be changed, the processproceeds to step S603, and the CPU 201 determines whether a sheet of thesame type as the sheet previously set in the sheet feeder set to bechanged in step S601 is set in another sheet feeder. Here, in a casewhere a sheet of the same type as the previous sheet is in another sheetfeeder, the process proceeds to step S605, otherwise, the processproceeds to step S604. In step S604, because the pre-change sheet typewill not be used in any of the sheet feeders, the CPU 201 deletes thesheet's reference information and the correction information (TBL 881(FIG. 8BB) and TBL 883 (FIG. 8BC) described below) from the referenceinformation storing module 311 and the correction information storingmodule 310, and the process proceeds to step S605. In step S605, the CPU201 deletes the record of the type information of the sheet of the sheetfeeder to have its settings changed from a reference informationmanagement table and a correction information management table. In thisembodiment, records include the items in FIGS. 8BA to 8BC, namely sheettype 891, target sheet feeder 892, reference information (½ speed) 893,reference information (1/1 speed) 894, generated page ID 895, start dateand time 896.

FIG. 6B is a flowchart for describing the processing by the referenceinformation storing module 311 and the correction information storingmodule 310 when a color measurement result notification is received fromthe color measuring sensor control module 312 in step S424 of FIG. 4described above.

In step S620, the CPU 201 functions as the reference information storingmodule 311 and obtains the color measurement result from the colormeasuring sensor control module 312. Next, the process proceeds to stepS621, and the CPU 201 functions as the reference information storingmodule 311 and determines whether or not a record of the sheet feederassociated with the color measurement result notified of by the colormeasuring sensor control module 312 is registered in the referenceinformation management table. In a case where no registration isdetermined, the process proceeds to step S622. In a case where aregistration is determined to be present, the process proceeds to stepS626.

In step S622, the CPU 201 functions as the reference information storingmodule 311 and determines whether or not a record of the sheet typeassociated with the color measurement result notified by the colormeasuring sensor control module 312 is registered with another sheetfeeder by referencing the reference information management table. In acase where no registration is determined, the process proceeds to stepS623. In step S623, the CPU 201 functions as the reference informationstoring module 311 and stores the color measurement result notified bythe color measuring sensor control module 312 as the referenceinformation (TBL 881 in FIG. 8BB as described below). Then, the processproceeds to step S624, and the CPU 201 functions as the referenceinformation storing module 311 and adds the record of the sheet feederassociated with the color measurement result notified by the colormeasuring sensor control module 312 to the reference informationmanagement table and executes link processing to reference the referenceinformation stored in step S623. Then, the process ends.

On the other hand, in step S622, in a case where the CPU 201 determinesthat a record of the sheet type associated with the color measurementresult notified by the color measuring sensor control module 312 isregistered with another sheet feeder, the process proceeds to step S625.In step S625, the CPU 201 functions as the reference information storingmodule 311, and copies the record of the type of the same sheet alreadyregistered in the reference information management table as a record ofthe sheet feeder associated with the color measurement result notifiedof by the color measuring sensor control module 312, in the referenceinformation management table. In this manner, the reference informationof the sheet type can be stored. Next, the process proceeds to stepS626, and the CPU 201 functions as the reference information storingmodule 311 and calculates the correction information from themeasurement value and the reference information and notifies thecorrection information storing module 310 of the calculated correctioninformation (TBL 883 in FIG. 8BC as described below). Then, in stepS627, the CPU 201 functions as the correction information storing module310 and stores the contents notified of by the reference informationstoring module 311 as correction information. Then, the process ends.

FIGS. 7A and 7B are diagrams illustrating examples of screens forregistering sheet types with sheet feeders of the printing apparatus 101according to the embodiment. The screens of FIGS. 7A and 7B will bedescribed with reference to the processing sequence of FIG. 5 describedabove.

FIG. 7A illustrates a feeder settings screen for the sheet feedersdisplayed by the UI control module 316. When the user calls up thefeeder settings screen in step S501 of FIG. 5 , in step S502, the UIcontrol module 316 queries the sheet feeder managing module 313 for thecurrent feeder settings information. Then, in step S503, the result isdisplayed on the UI screen 700.

The user selects the sheet feeder to set the sheet type via the UIscreen 700. In this embodiment, the selection buttons 701 to 704 areallocated corresponding to the four sheet feeders of the printingapparatus 101. After the user selects a specific sheet feeder, in stepS504, when a settings button 705 for setting the sheet type is pressed,the list 710 for sheet type of FIG. 7B is displayed (step S505). Notethat at the time of FIG. 7A, the sheet feeder corresponding to thesettings button 705 is set as A4 size “plain paper 1”.

At the list 710 for sheet type, one selection matching the sheet typeset/to be set in the sheet feeder selected at the UI screen 700 isselected. In the example of FIG. 7B, a change is being instigated fromsheet type “plain paper 1” to “plain paper 3” for the sheet feedercorresponding to the selection button 701 (step S506). Then, when an OKbutton 708 of FIG. 7B is pressed, the UI screen 700 is returned to. Toconfirm the change to the sheet type of the desired sheet feeder, theuser presses an OK button 706. In response to this, the UI controlmodule 316 notifies the sheet feeder managing module 313 of the usersheet settings (step S507) and performs a registration request.

FIGS. 8BA to 8BC are diagrams for describing information of a managementtable of the printing apparatus 101 according to the embodiment. Thismanagement table stores the print position of the tone correction marks(tone patches) for tone correction, the color sensor for measuring theprinted color patches, and signal values from the color sensor andcorrection information derived from the signal values.

FIG. 8AA is a diagram for describing an output example of tonecorrection marks (tone patches) targeted for real time tone correctionaccording to the embodiment.

The patches necessary for performing real time multi-tone correction areprinted on the inner side of a print sheet 800 and on the outer side ofa print assurance region 801 of the print sheet 800 in defined marginareas on both sides. The print assurance region 801 is portion thatcorresponds to the final product and is a region assured for printingthe user image. The area outside of the print assurance region 801 isalso an area where an image may be formed, however, this area isintended to be cut or removed from the final product. Note that the areamay be used with a Print-on-Demand (POD) device for printing variouspatches required for image quality adjustment or information requiredfor inspection.

The real time tone correction patches are printed side by side on theouter side of the print assurance region 801 and read by sensors 861,862 on the print surface side. Thus, the color patches are disposed sideby side in the conveyance direction aligned with the position of thesensors 861, 862. Cyan patches 810, magenta patches 850, yellow patches830, and black patches 840 are printed on the print sheet 800. Thepatches of each color include ten patches with toner density differingby increments of 10%, and with four colors, a total number of 40 patchesare printed.

For example, in the cyan color patches 810, the patch furthest to theleft has a density of 100%, and toward the right, the density decreasesby increments of 10% (predetermined density unit), with the patchfurthest to the right having a density of 10%. Each set of the colorsmagenta, yellow, and black are made up of ten patches in the samemanner. Then, with the data of the reference information and themeasurement values of the four colors ready, feedback needed for tonecorrection can be generated for the first time. The tone correctionpatches are combined with the image generated by the image generationmodule 307 by the patch combining module 309.

FIG. 8AB depicts a view illustrating a cross-sectional view, as seenfrom the side, of the conveyance path of the printing apparatus 101 whenprinting the patches of FIG. 8AA. Developing devices 871 to 874 of thecolors C, M, Y, and K transfer toner to the print sheet 800, before afixing device 875 executes fixing processing. The patches 810, 830, 840,850 of each color are read by the color sensors 861, 862 installed onthe left and the right at the end in the conveyance direction. The colorsensors 861, 862 are installed on the print surface side.

FIG. 8BA is a diagram illustrating an example of the referenceinformation, the measurement values, and the correction informationgenerated on the basis of the CMYK density information scanned by thecolor sensors 861, 862.

10 patches of each color, C, M, Y, and K, totaling 40 patches areprinted on the print sheet 800 of FIG. 8AA. Thus, 40 measurement valuesare obtained by the color sensors 861, 862 reading the patches. In thisexample, the color measuring sensor control module 312 stores the patchdensities as numerical values of 1024 levels. The color measurementresults notified by the color measuring sensor control module 312 areheld in the reference information storing module 311 as referenceinformation for each type of sheet set in the sheet feeders. The colormeasurement results need to be managed per sheet type. In a case wherethe color measurement results of the sheet notified by the colormeasuring sensor control module 312 are those of a sheet of a typeunregistered in the reference information storing module 311, 40 pointcolor measurement results are stored as new reference information 881(FIG. 8BA).

On the other hand, in a case where color measurement results of a sheetnotified of by the color measuring sensor control module 312 are thoseof a sheet of a type registered in the reference information storingmodule 311, the color measurement results are treated as new measurementvalues 882, and correction information 883 (FIG. 8BA) are calculatedfrom the difference between the reference information and themeasurement value. These items of correction information are stored bythe correction information storing module 310. Note that in theembodiment, the correction information is stored. However, themeasurement values may be stored, and the correction information may becalculated from the difference between the reference information and themeasurement values each time it is used.

FIG. 8BB depicts a view illustrating an example of a management tableused by the reference information storing module 311 to manage thereference information. The record information of the management tableincludes the sheet type 891, the target sheet feeder 892, the referenceinformation (½ speed) 893, the reference information (1/1 speed) 894,the generated page ID 895, the start date and time 896. The referenceinformation of the management table indicates that “plain paper 3” isset in “feeder 1 (CST1)”, and since the power was turned on at a startdate and time of “10:04:06 on 2019 Jul. 18”, a printing processing ofthe 60014th page cumulatively speaking is being executed. At this time,“plain paper 3” is being feed from “feeder 1” at “1/1 speed”, and theprint result is registered as the color measuring and referenceinformation. Note that in a case where “plain paper 3” is removed from“feeder 1”, this record information is deleted.

FIG. 8BC depicts a view illustrating an example of a table used by thecorrection information storing module 310 to manage the correctioninformation. The basic configuration of this table is the same as themanagement table of FIG. 8BB, except that the reference information isreplaced with the correction information. Also here, in a case where thesheet is removed from the target sheet feeder 897, the recordinformation of the sheet is deleted.

FIG. 9 depicts a view illustrating an example of a table 901 indicatingwhether the sheet is a large size sheet or a small size sheet.

Indicated in the table 901 is that an A3 sheet is a large size 902 andan A4 sheet is a small size 903. The table 901 is used in determiningwhether each sheet is a small size sheet or a large size sheet in theprocessing of combining the tone patches described below.

FIGS. 10A and 10B are diagrams illustrating output examples of patchestargeted for real time multi-tone correction according to sheet sizethat are printed by the printing apparatus 101 according to theembodiment.

In order for the inline sensor to accurately read the patches, the sizeof each of the cyan patches 810, the magenta patches 850, the yellowpatches 830, and the black patches 840 illustrated in FIG. 8AA ispredetermined. For example, in a case where the size of one patch in theconveyance direction is 11 mm, in order to continuously print tenpatches at increments of 10% in terms of toner single color density, thelength of a set of color patches needs to be 11 mm multiplied by 10,i.e., 110 mm. Furthermore, as illustrated in FIG. 8AB, in a case wherethe cyan patches 810 and the yellow patches 830 are disposed along theconveyance direction, the length of two sets of color patches needs tobe 220 mm or greater in the conveyance direction. Thus, the printingapparatus 101 needs to perform printing while changing the patch outputmethod depending on the length of the sheet size in the conveyancedirection.

FIG. 10A is a diagram illustrating an output example in a case of asheet size with a sufficient region to form the necessary patches. Inthis case, as with that of FIG. 8AA, cyan patches 1002, magenta patches1005, yellow patches 1003, and black patches 1004 including ten patches(10 levels) of 10% increments in toner single color density can beprinted on a print sheet 1000, the total number of patches totaling 40.

FIG. 10B is a diagram illustrating an output example in a case of asheet size with an insufficient region to form the necessary patches. Inthis case, the patches are printed on two sheets, a print sheet 1010 anda print sheet 1020. A total of 20 patches are printed on the print sheet1010, with ten patches (ten levels) of cyan patches 1012 and blackpatches 1013 of 10% increments in toner single color density. Also, atotal of 20 patches are printed on the print sheet 1020, with tenpatches (ten levels) of yellow patches 1022 and magenta patches 1023 of10% increments in toner single color density.

The patches for image quality adjustment are patches of each color,cyan, magenta, yellow, and black, and in order to perform adjustment,data of the patches of all the colors must be prepared. In a case wherethe sheet size has a region sufficient for printing the necessarypatches, patch data of all the colors, cyan, magenta, yellow, and black,can be printed on a single sheet. Thus, image quality adjustment can beperformed using just one sheet. On the other hand, in a case where thesheet size does not have a region sufficient for printing the necessarypatches, for example, cyan and magenta patches are printed on a firstsheet and yellow and black patches are printed on a second sheet. Inthis case, two sheets must be prepared in order to perform coloradjustment.

Various pieces of image data are entered by users. For example, a usermay enter data that includes both a sheet able to accommodate thepatches on a single sheet and a sheet with a size which requires thepatches to be printed across a plurality of sheets.

FIGS. 12A to 12C are diagrams illustrating examples of sheets on whichpatches for real time multi-tone correction have been printed. Asillustrated in FIGS. 12A and 12B, in the data, the sheet sizes may allbe the same, for example. Or as illustrated in FIG. 12C, in the data, aplurality of sheet sizes may be present. In a case where the data ofFIG. 12B is output, because sheets 1211 to 1214 have a size able toaccommodate the patches on a single sheet, adjustment can start by justreading a single sheet.

On the other hand, as illustrated in FIG. 12A, because sheets 1201 to1207 have a size that is unable to accommodate the patches on a singlesheet, the patches must be printed divided across two sheets. In thiscase, adjustment can start when all of the divided patches are read, orin other words, when the patches of the two sheets are read.

In comparison, as illustrated in FIG. 12C, there are cases with acombination of sheet 1221 and 1223 with a size able to accommodate thepatches on a single sheet and sheets 1222 and 1224 to 1227 which requirethe patches to be printed across a plurality of sheets. This case isproblematic because correction cannot start until, after the patches ofthe first sheet is detected, the next second sheet 1224 is read afterthe second sheet 1222. In a case such as this when an interval existsbetween the first and second sheets that include a single set ofpatches, the state of the printing apparatus when printing thesubsequent patches changes. Thus, image quality adjustment may beperformed using measuring results of incorrect patches.

FIG. 11 is a flowchart for describing the processing to determinewhether or not to perform real time multi-tone correction using theprinting apparatus 101 according to the embodiment. An example of a casein which four types of patches are required to be read will be describedusing FIG. 11 . The operations of the flowchart are implemented by theCPU 201 deploying a program stored in the ROM 202 on the RAM 203 andexecuting the program. Herein, the name of the components will be madethe subject of the sentences to make clear which component implementsthe processing.

First, in step S1101, the CPU 201 determines whether reading by thecolor measuring sensor control module 312 of the color measuring targetsheets output (printed) with the received PDL data is complete, or, inother words, whether all of the sheets have been confirmed. In a casewhere it is determined that confirmation of all of the sheets is notfinished, the process proceeds to step S1102. In a case where it isdetermined that confirmation of all of the sheets is finished, theprocess ends. In step S1102, the CPU 201 uses the color measuring sensorcontrol module 312 to read the patches from the sheets printed with thereceived PDL data. Then, the process proceeds to step S1103, and the CPU201 obtains the sheet size of the sheets read in step S1102 from theengine control module 308. Next, the process proceeds to step S1104, andthe CPU 201 determines whether the size of the read sheet is large orsmall. In this embodiment, large or small is determined in accordancewith the table illustrated in FIG. 9 . In a case where the read sheet isdetermined to be sorted into the large sheets, the process proceeds tostep S1105. In a case where the read sheet is determined to be sortedinto the small sheets, the process proceeds to step S1108.

In step S1105, the CPU 201 initializes a holding unit (provided in theRAM 203 or the storage 204) that temporarily stores the information ofthe read patches. Then, the process proceeds to step S1106, and the CPU201 stores the information of the read patches in the holding unit. Inthis embodiment, four sets of patches are read. Thus, the information ofthe read patches is used as measurement values to calculate thecorrection information 883 of FIG. 8BA. Then, the process proceeds tostep S1107, and the CPU 201 sets the stored patch information as thecolor measurement data obtained by the color measuring sensor controlmodule 312. Next, the CPU 201 proceeds the process to step S1102. Inthis case, by only reading the patches of a single sheet, the requiredpatch information is obtained.

In step S1108, because the sheets were sorted as small sheets, the CPU201 needs to read the patches on two small sheets. Thus, in step S1108,the CPU 201 determines the size information of the sheet one previous.In a case where the one previous read sheet is a large sheet or no sheetis present, the process proceeds to step S1109. In a case where the oneprevious read sheet is sorted as a small sheet, the process proceeds tostep S1111. In step S1109, the CPU 201 initializes the holding unit thattemporarily stores the information of the read measurement patches.Then, the process proceeds to step S1110, and the CPU 201 stores theinformation of the two sets of read patches in the holding unit. Then,to read the patches of the second small sheet, the process proceeds tostep S1102.

In step S1111, in a case where the one previous read sheet and thecurrent read sheet are both small size sheets, the CPU 201 stores theinformation of the two sets of read patches. In this manner, two smallsheets are read one after another and information of the four sets ofrequired patches has been obtained in order to calculate the correctioninformation 883. Then, the process proceeds to step S1107. Then, the CPU201 sets the stored patch information as the color measurement dataobtained by the color measuring sensor control module 312 and proceedsthe process to step S1102. In this case, by reading the patches of twosheets one after another, the required patch information is obtained.

Note that in this embodiment, in a case of a large sheet, the colormeasurement data is set by performing reading just once, and in a caseof a small sheet, the color measurement data is set as the measurementvalue by reading at least two sheets one after another. However, thetiming of when the color measurement data is read is not limited to thistiming. For example, in other cases, reading may be performed each timein order of a sheet for cyan patches and magenta patches and then asheet for yellow patches and black patches, in order of a sheet foryellow patches and black patches and then a sheet for cyan patches andmagenta patches, or in an order other than this. Also, in a case wheretwo or more sheets need to be measured, processing may be executed whena plurality of sheets can follow one after another. Furthermore, in acase where two or more sheets need to be measured patches, processingmay be executed when the sheets able to be used in correction areaready.

Also, in a case where the correction information cannot be obtainedbecause the sheets that need to be measured do not follow one afteranother, correction may be performed using the most recent correctioninformation or the correction information obtained by measuring thepatches of the most recent large sheet.

OTHER EMBODIMENTS

Embodiments of the present invention can also be realized by a computerof a system or apparatus that reads out and executes computer executableinstructions (e.g., one or more programs) recorded on a storage medium(which may also be referred to more fully as a ‘non-transitorycomputer-readable storage medium’) to perform the functions of one ormore of the above-described embodiments and/or that includes one or morecircuits (e.g., application specific integrated circuit (ASIC)) forperforming the functions of one or more of the above-describedembodiments, and by a method performed by the computer of the system orapparatus by, for example, reading out and executing the computerexecutable instructions from the storage medium to perform the functionsof one or more of the above-described embodiments and/or controlling theone or more circuits to perform the functions of one or more of theabove-described embodiments. The computer may comprise one or moreprocessors (e.g., central processing unit (CPU), micro processing unit(MPU)) and may include a network of separate computers or separateprocessors to read out and execute the computer executable instructions.The computer executable instructions may be provided to the computer,for example, from a network or the storage medium. The storage mediummay include, for example, one or more of a hard disk, a random-accessmemory (RAM), a read only memory (ROM), a storage of distributedcomputing systems, an optical disk (such as a compact disc (CD), digitalversatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, amemory card, and the like.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2020-109000, filed Jun. 24, 2020, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. A printing apparatus comprising: a printer enginethat prints an image on a sheet; a sensor that performs color measuringof tone correction patches printed on a sheet; one or more controllersincluding one or more processors and one or more memories, one or morecontrollers configured to: cause the printer engine to print first tonecorrection patches of a first color on a predetermined size of a firstsheet and to print second tone correction patches of a second colorbeing different from the first color on a predetermined size of a secondsheet; generate correction information based on a color measurementresult of the first tone correction patches and the second tonecorrection patches printed on the first sheet and the second sheet,respectively, as measured by the sensor; and correct image data usingthe correction information, wherein, in the generation of the correctioninformation, in a case where there are more than a predetermined numberof sheets of a size being different from the predetermined size betweenthe first sheet and the second sheet, the one or more controllers do notgenerate the correction information using the color measurement resultof the first tone correction patches and the second tone correctionpatches.
 2. The printing apparatus according to claim 1, wherein, in thegeneration of the correction information, in a case where there are notmore than the predetermined number of sheets of a size being differentfrom the predetermined size between the first sheet and the secondsheet, the one or more controllers generate the correction informationusing the color measurement result of the first tone correction patchesand the second tone correction patches.
 3. The printing apparatusaccording to claim 1, wherein the predetermined size is A4 size.
 4. Theprinting apparatus according to claim 1, wherein the size beingdifferent from the predetermined size is A3 size.
 5. The printingapparatus according to claim 1, wherein the one or more controllersfurther cause the printer engine to print third tone correction patchesof a third color on the first sheet and to print fourth tone correctionpatches of a fourth color on the second sheet.
 6. The printing apparatusaccording to claim 1, wherein, in the generation of the correctioninformation, in a case where there are a number of sheets between athird sheet and a fourth sheet whose sizes are different from thepredetermined size, the one or more controllers generate the correctioninformation regardless of the number of sheets.
 7. The printingapparatus according to claim 1, where the tone correction patches areprinted on sheets of a plurality of sizes.
 8. The printing apparatusaccording to claim 1, where the plurality of sizes include A4 size andA3 size.
 9. A method of controlling a printing apparatus having aprinter engine that prints an image on a sheet and a sensor thatperforms color measuring of tone correction patches printed on a sheet,the method comprising: causing the printer engine to print first tonecorrection patches of a first color on a predetermined size of a firstsheet and to print second tone correction patches of a second colorbeing different from the first color on a predetermined size of a secondsheet; generating correction information based on a color measurementresult of the first tone correction patches and the second tonecorrection patches printed on the first sheet and the second sheet,respectively, as measured by the sensor; and correcting image data usingthe correction information, wherein, in the generation of the correctioninformation, in a case where there are more than a predetermined numberof sheets of a size being different from the predetermined size betweenthe first sheet and the second sheet, the correction information is notgenerated using the color measurement result of the first tonecorrection patches and the second tone correction patches.
 10. Themethod of controlling the printing apparatus according to claim 9,wherein, in the generation of the correction information, in a casewhere there are not more than the predetermined number of sheets of thesize being different from the predetermined size between the first sheetand the second sheet, the correction information is generated using thecolor measurement result of the first tone correction patches and thesecond tone correction patches.
 11. The method of controlling theprinting apparatus according to claim 9, wherein the predetermined sizeis A4 size.
 12. The method of controlling the printing apparatusaccording to claim 9, wherein the size being different from thepredetermined size is A3 size.
 13. The method of controlling theprinting apparatus according to claim 9, further comprising: causing theprinter engine to print third tone correction patches of a third coloron the first sheet and to print fourth tone correction patches of afourth color on the second sheet.
 14. The method of controlling theprinting apparatus according to claim 9, wherein, in the generation ofthe correction information, in a case where there are a number of sheetsbetween a third sheet and a fourth sheet whose sizes are different fromthe predetermined size, the correction information is generatedregardless of the number of sheets.
 15. The method of controlling theprinting apparatus according to claim 9, where the tone correctionpatches are printed on sheets of a plurality of sizes.
 16. The method ofcontrolling the printing apparatus according to claim 9, where theplurality of sizes include A4 size and A3 size.
 17. A non-transitorycomputer-readable storage medium storing a program for causing aprocessor to execute a method of controlling a printing apparatus havinga printer engine that prints an image on a sheet and a sensor thatperforms color measuring of tone correction patches printed on a sheet,the method comprising: causing the printer engine to print first tonecorrection patches of a first color on a predetermined size of a firstsheet and to print second tone correction patches of a second colorbeing different from the first color on a predetermined size of thesecond sheet; generating correction information based on a colormeasurement result of the first tone correction patches and the secondtone correction patches printed on the first sheet and the second sheet,respectively, as measured by the sensor; and correcting image data usingthe correction information, wherein, in the generation of the correctioninformation, in a case where there are more than a predetermined numberof sheets of a size being different from the predetermined size betweenthe first sheet and the second sheet, the correction information is notgenerated using the color measurement result of the first tonecorrection patches and the second tone correction patches.